Inhibitory effect of mast cell-mediated immediate-type allergic reactions by Cichorium intybus

We investigated the effect of an aqueous extract of Cichorium intybus (CIAE) on mast cell-mediated immediate type allergic reactions. CIAE (0.1-1000 mg kg^-1) dose-dependently inhibited systemic anaphylactic reaction induced by compound 48/80 in mice. Especially, CIAE inhibited compound 48/80-induced anaphylactic reaction 100% with the dose of 1000 mg kg^-1. CIAE 1000 mg kg^-1 also significantly inhibited local anaphylactic reaction activated by anti-dinitrophenyl (DNP) IgE. When mice were pretreated with CIAE at a concentration ranging from 0.1 to 1000 mg kg^-1, the plasma histamine levels were reduced in a dose-dependent manner. CIAE (1-1000 μg ml^-1) dose-dependently inhibited histamine release from the rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. The level of cAMP in RPMC, when CIAE (1000 μg ml^-1) was added, increased significantly compared with that of control cells. These results indicate that CIAE inhibits mast cell-mediated immediate-type allergic reactions in vivo and in vitro.